Hygrophila Polysperma

Hygrophila polysperma is one of the most effortless stem plants in the hobby. Its light green, elongated oval leaves are arranged in opposite pairs; in strong light a faint pinkish-bronze color appears on the top leaves. It grows across a wide range, from soft to hard water and between 20 and 30 °C; it needs no CO₂ or special fertilizer.

Because it grows very fast, it uses up excess nutrients in the water and helps keep algae at bay. This makes it especially useful in newly set-up aquariums. The pink-veined 'Rosanervig' form is also common.

Do not release it into the wild: In the United States this species is on the list of prohibited noxious weeds as an invasive, and in warm-climate regions it can choke natural waters. Trimmings should go in the trash.

• The stems are separated one by one, the lower leaves are removed and they are buried 3–4 cm deep.
• Leave about 3 cm between stems; plant in clusters in the background and corners.
• Because it grows fast, it is placed not directly behind the slow plants in the foreground but in back areas that are easy to trim.

• Light: Medium; it also survives in low light, but the internodes become longer.
• CO₂: Not required.
• Fertilizer: Occasional liquid fertilizer is enough; during periods of very fast growth, a lack of nutrients can turn the leaves yellow.
• Trimming: Cut from the top once a week or every two weeks. If not cut, it spreads across the surface and shades the plants below.

It propagates very easily from top cuttings. Even small broken-off stem pieces can root and become new plants, so do not leave trimmings floating in the aquarium.

• Overrunning the aquarium: If its fast growth is not controlled, it smothers other plants; regular trimming is needed.
• Holes in the leaves: Usually potassium deficiency.
• Yellowing lower leaves: Lack of nutrients or light.
• Plant-eating fish: Silver dollars and some large cichlids eat its soft leaves.